I love the Laura storyline. Diana Millay is brilliant. It's clear to see that Alexandra Moltke enjoyed what she was doing, and Vicki was not only an integral part of the plot, she had a brain and she used it. Actually, the storyline was a triumph in one way or another for all the core cast and characters as everyone already had or came to have some connection/involvement with Laura and her plans for David. It was a well thought out and intricately plotted story that provided meaty material for everyone involved to work with. And what's truly sad is that it doesn't get the attention/credit it deserves because the decision to extend DS beyond the six months it had to prove itself or face cancellation was made by ABC during the Laura storyline. In large part the popularity of Barnabas gave DS an even longer run, but it was the audience's response to Laura that first saved the show.
I personally think that the Laura story was an amazing preamble to what was to come on DS. I absolutely love the fact that this story is a great supernatural tale that is also composed of traditional soap elements as well. I think that if DS would have continued with this mantra instead of all manner of supernatural creatures running amok (1968 anyone) then the show perhaps wouldn't have ran out steam as quickly.
Well, during the Laura storyline Art Wallace was still the head writer. But in 1968, well, he wasn't - DC had proclaimed himself as head writer and Wallace was sadly long gone...